From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id DD694C4167B for ; Tue, 28 Nov 2023 01:00:30 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=Pjq/Cf0/; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4SfPJY3Tq7z3cbW for ; Tue, 28 Nov 2023 12:00:29 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=ellerman.id.au header.i=@ellerman.id.au header.a=rsa-sha256 header.s=201909 header.b=Pjq/Cf0/; dkim-atps=neutral Received: from gandalf.ozlabs.org (mail.ozlabs.org [IPv6:2404:9400:2221:ea00::3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4SfPHc2sC0z3c2H for ; Tue, 28 Nov 2023 11:59:40 +1100 (AEDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1701133179; bh=C+WoRpLz4ShCJ4XjCw9fNycJzhe2kxDftUueiTVyaKs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Pjq/Cf0/z/HjG03/EP2bb0mnMNe51x2mxMm9n1J3jZOLtkfmLEZlIz3G4g1RDXuqm Hgt/KkoMn7pdM75wkf8dhBPxAfcBVMo5VDTk61SsYvBiwsye/A+8DFpg2v7dKqhp5D xBob1guuriG237cOzgfyBA2MfBV2KaUiO2qM3fY5TfGFmiArEBseknn7I/3/3O+iA5 a+637wNwjBm7OjYHztaCfl1O310XYvZ3Vuhf2ifBMtIhWKyZxyTtvNFqedI8FJ7drM GQYd+1gw4+57gj2GUQVWYcaLmLSTjR8Bt6mtmykG5Cme7EHM6+8oQKOlagTaEuFksl Ha1n9HqhtFK+g== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4SfPHb32Qhz4wc8; Tue, 28 Nov 2023 11:59:39 +1100 (AEDT) From: Michael Ellerman To: Christophe Leroy , Timothy Pearson Subject: Re: [PATCH v2] powerpc: Don't clobber fr0/vs0 during fp|altivec register save In-Reply-To: <89de310e-bb9a-4485-bc8c-3fbefc90e6f6@csgroup.eu> References: <1921539696.48534988.1700407082933.JavaMail.zimbra@raptorengineeringinc.com> <877cmc7ve9.fsf@mail.lhotse> <439072392.48800901.1700498743840.JavaMail.zimbra@raptorengineeringinc.com> <874jhg6lkn.fsf@mail.lhotse> <1294229534.48922001.1700539832331.JavaMail.zimbra@raptorengineeringinc.com> <87leaqjs8x.fsf@mail.lhotse> <1340817182.49635143.1700784119445.JavaMail.zimbra@raptorengineeringinc.com> <1276384468.50536225.1701110354677.JavaMail.zimbra@raptorengineeringinc.com> <89de310e-bb9a-4485-bc8c-3fbefc90e6f6@csgroup.eu> Date: Tue, 28 Nov 2023 11:59:35 +1100 Message-ID: <871qca4rrc.fsf@mail.lhotse> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jens Axboe , linuxppc-dev , regressions , npiggin Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Christophe Leroy writes: > Le 27/11/2023 =C3=A0 19:39, Timothy Pearson a =C3=A9crit=C2=A0: >> Just wanted to check back and see if this patch was going to be >> queued up soon? We're still having to work around / advertise the >> data destruction issues the underlying bug is causing on e.g. Debian >> Stable. > > Has any agreement been reach on the final solution ? Seeing the many=20 > discussion on patch v2 I had the feeling that it was not the final soluti= on. The actual patch is fine I think. The discussion was about improving the explanation of exactly what's happening in the change log, and whether there is a larger bug causing FP corruption unrelated to io-uring. I'm now reasonably confident there's no detectable corruption of fr0 happening except via the io-uring -> clone path. It's still a bad bug for us to corrupt fr0 across sys_clone(), but in practice it doesn't affect userspace because fr0 is volatile across function calls. cheers From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 173501100 for ; Tue, 28 Nov 2023 00:59:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ellerman.id.au Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ellerman.id.au Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ellerman.id.au header.i=@ellerman.id.au header.b="Pjq/Cf0/" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ellerman.id.au; s=201909; t=1701133179; bh=C+WoRpLz4ShCJ4XjCw9fNycJzhe2kxDftUueiTVyaKs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Pjq/Cf0/z/HjG03/EP2bb0mnMNe51x2mxMm9n1J3jZOLtkfmLEZlIz3G4g1RDXuqm Hgt/KkoMn7pdM75wkf8dhBPxAfcBVMo5VDTk61SsYvBiwsye/A+8DFpg2v7dKqhp5D xBob1guuriG237cOzgfyBA2MfBV2KaUiO2qM3fY5TfGFmiArEBseknn7I/3/3O+iA5 a+637wNwjBm7OjYHztaCfl1O310XYvZ3Vuhf2ifBMtIhWKyZxyTtvNFqedI8FJ7drM GQYd+1gw4+57gj2GUQVWYcaLmLSTjR8Bt6mtmykG5Cme7EHM6+8oQKOlagTaEuFksl Ha1n9HqhtFK+g== Received: from authenticated.ozlabs.org (localhost [127.0.0.1]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mail.ozlabs.org (Postfix) with ESMTPSA id 4SfPHb32Qhz4wc8; Tue, 28 Nov 2023 11:59:39 +1100 (AEDT) From: Michael Ellerman To: Christophe Leroy , Timothy Pearson Cc: Jens Axboe , regressions , npiggin , linuxppc-dev Subject: Re: [PATCH v2] powerpc: Don't clobber fr0/vs0 during fp|altivec register save In-Reply-To: <89de310e-bb9a-4485-bc8c-3fbefc90e6f6@csgroup.eu> References: <1921539696.48534988.1700407082933.JavaMail.zimbra@raptorengineeringinc.com> <877cmc7ve9.fsf@mail.lhotse> <439072392.48800901.1700498743840.JavaMail.zimbra@raptorengineeringinc.com> <874jhg6lkn.fsf@mail.lhotse> <1294229534.48922001.1700539832331.JavaMail.zimbra@raptorengineeringinc.com> <87leaqjs8x.fsf@mail.lhotse> <1340817182.49635143.1700784119445.JavaMail.zimbra@raptorengineeringinc.com> <1276384468.50536225.1701110354677.JavaMail.zimbra@raptorengineeringinc.com> <89de310e-bb9a-4485-bc8c-3fbefc90e6f6@csgroup.eu> Date: Tue, 28 Nov 2023 11:59:35 +1100 Message-ID: <871qca4rrc.fsf@mail.lhotse> Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Christophe Leroy writes: > Le 27/11/2023 =C3=A0 19:39, Timothy Pearson a =C3=A9crit=C2=A0: >> Just wanted to check back and see if this patch was going to be >> queued up soon? We're still having to work around / advertise the >> data destruction issues the underlying bug is causing on e.g. Debian >> Stable. > > Has any agreement been reach on the final solution ? Seeing the many=20 > discussion on patch v2 I had the feeling that it was not the final soluti= on. The actual patch is fine I think. The discussion was about improving the explanation of exactly what's happening in the change log, and whether there is a larger bug causing FP corruption unrelated to io-uring. I'm now reasonably confident there's no detectable corruption of fr0 happening except via the io-uring -> clone path. It's still a bad bug for us to corrupt fr0 across sys_clone(), but in practice it doesn't affect userspace because fr0 is volatile across function calls. cheers